The present invention relates generally to a blow molding machine and particularly, to an automatic operation control of the blow molding machine from a completion of production of one product to a start of production of a next product.
The blow molding machine is a machine which serves to make resin hollow moldings in accordance with the shape of a cavity formed in a mold held by a mold clamping unit. Upon molding operation, parisons as supplied from an extruder are received in the mold, and subjected to air blown out of a calibrating unit.
Due to a diversity of resin hollow moldings, it is necessary to prepare molds as well as molding jigs such as a blow pin, die and core which are adapted thereto.
An installation of a plurality of blow molding mchines to correspond to different types of resin hollow moldings is uneconomical, so that a single blow molding machine is generally used wherein different types of resin hollow moldings are formed by changing the molds and the molding jigs.
Conventionally, an exchange of the molds and the molding jigs are carried out manually, and not automatically. This does not allow a continuous operation of the blow molding machine.
With such a manual exchange, however, the operator can drop the mold having a heavy weight even when using a lifter, a roller, etc., resulting in a possible injury.
Further, when mounting and detaching the die and core, a scrubbing of the resin is also needed, which may cause a burn to the operator.
Furthermore, an exchange of the blow pin accompanies a centering operation thereof in addition to a mounting and detaching of water and air pipes, which needs hands and time.
The blow molding machine can continuously be operated by automatic control from a start of production of one product to a completion of production thereof, however, it cannot automatically carry out a preparation from a completion of production of one product to a start of production of a next product.
One solution of the problem to an automatic preparation from a completion of production of one product to a start of production of a next product is the use of a so-called robot, which is, however, unsuitable for the blow molding machine due to high cost and required space.
It is, therefore, an object of the present invention to provide a blow molding machine which enables an automatic preparation from a completion of production of one product to a start of production of a next product.